The
mouth is actually a magic mouth that has gone feral. It will
use its tongue to try to grab adventurers and drag them to its
orifice. It can make only one attack per round, but upon being
struck by its tongue, the victim must succeed on a saving throw
versus paralyzation or suffer paralysis.

If
he victim is paralyzed, or in any case if the mouth makes an attack
that succeeds by greater than 4 than it requires on its “to hit”
roll, the victim is grabbed an will be brought to the mouth to be
chewed for 1d8 damage. The mouth can only fit creatures up to about
the size of a donkey or ogre. The individual will then be deposited
in Room 52 on the Third and a Half Floor.

The
hit points represent those of the tongue, which can regenerate 2 hit
points per round. If the tongue is destroyed the mouth is dispelled.
The fleshy lips can be attacked (as AC 10) if targeted and will
appear to bleed, but all such damage is cosmetic only. The magic
mouth can also be dispelled by a dispel magic spell, but
treat it as being cast by a 24th level magic-user.